Energy-Oriented Inter-Vehicle Distance Optimization for Heterogeneous E-Platoons

The development of Connected and Autonomous Vehicles (CAVs) has the potential to improve the energy efficiency of the transportation system. Since the inter-vehicle distance plays a crucial role for energy-saving purposes, this paper proposes a novel optimization algorithm to compute the optimal gap distance in a heterogeneous platoon of electric CAVs by exploiting a distance-dependent air drag coefficient formulation. Specifically, the proposed method exploits the leader speed and acceleration profiles information, as well as road slope one, to compute the optimal inter-vehicle distance w.r.t. the preceding vehicle so as to reduce the air-drag coefficient and, hence, reduce energy consumption. The proposed algorithm exploits Nonlinear Programming method, taking into account safety constraints in order to avoid collisions among vehicles. The effectiveness of the approach is evaluated via the Matlab/Simulink simulation platform by considering two driving scenarios, namely base scenario, where the Constant Time Headway spacing policy is adopted, and optimized scenario, where the proposed algorithm is exploited to compute the optimal inter-vehicle distances. Numerical results confirm the effectiveness of the proposed optimization strategy in reducing energy consumption w.r.t. base scenario.